Field of the Invention
The present invention relates to a cutting device and a cutting method for cutting an object to be cut to manufacture a plurality of singularized products.
Description of the Background Art
A substrate made of a printed circuit board, a lead frame or the like is imaginarily partitioned into a plurality of lattice-shaped regions. Then, after one chip-shaped element or a plurality of chip-shaped elements (for example, a semiconductor chip) is/are mounted on each of the regions, the entire substrate is resin-sealed. The resulting product obtained in this way is referred to as a “sealed substrate”. The sealed substrate is cut by a cutting mechanism employing a rotary blade or the like and singularized into region units, each of which is provided as a product.
Conventionally, a cutting device has been used to cut a prescribed region of the sealed substrate by a cutting mechanism such as a rotary blade. First, the sealed substrate is placed on a cutting table. Then, the sealed substrate is aligned (positioned). By such alignment, the position of each imaginary cutting line for partitioning the sealed substrate into a plurality of regions is set. Then, the cutting table on which the sealed substrate is placed and the cutting mechanism are moved relative to each other. While cutting water is sprayed onto to an area of the sealed substrate that should be cut, the sealed substrate is cut by the cutting mechanism along each cutting line defined on the sealed substrate. The sealed substrate is cut, thereby manufacturing singularized products.
The cutting table is equipped with a cutting jig adaptable to products. The sealed substrate is placed on the cutting jig and adhered thereto by means of vacuum sucking. The cutting jig is provided with a plurality of platform-shaped protrusions sucking a plurality of regions, respectively, in the sealed substrate so as to be held thereon. The plurality of protrusions are provided with sucking holes, respectively. Between the protrusions, a plurality of cutting grooves are provided that correspond to the positions of the plurality of cutting lines, respectively, partitioning the sealed substrate into a plurality of regions. The cutting table and the cutting mechanism move relative to each other, so that the sealed substrate is cut along the plurality of cutting lines and thereby singularized.
When the sealed substrate is cut, each cutting line of the sealed substrate is aligned with the position of each cutting groove on the cutting jig. The rotary blade is moved along each cutting line to thereby cut the sealed substrate. When the sealed substrate is cut in the state where the position of a cutting groove on the cutting jig and the position of a cutting line on the sealed substrate are displaced from each other, the rotary blade may be displaced from the position of the cutting groove, so that a part of the cutting jig may be shaved. The cutting jig is shaved, so that a large amount of scraps are generated. Furthermore, the cutting jig is shaved, thereby shortening the life of the cutting jig. Therefore, it becomes important to cut the sealed substrate while accurately aligning the position of each cutting line on the sealed substrate with the position of each cutting groove on the cutting jig.
As a cutting device capable of holding a workpiece on a holding table so as to align dividing lines with the positions of cutting blade clearance grooves, respectively, even if each dividing line undergoes a pattern displacement, there is a proposed cutting device “comprising: a rotatable holding table holding a workpiece, the holding table having a cutting blade clearance groove formed at a position corresponding to a dividing line on the surface of the workpiece; cutting means having a cutting blade for cutting the workpiece held in the holding table along the dividing line; and conveying means for conveying the workpiece onto the holding table, the cutting device further comprising control means for controlling the conveying means or the holding table to cause the workpiece to be held on the holding table while aligning the dividing line on the surface of the workpiece recognized by imaging module with the position of the cutting blade clearance groove on the holding table (for example, see paragraph [0009], FIGS. 1, 4 and 5 in Japanese Patent Laying-Open No. 2009-170501).
As shown in FIGS. 4 and 5 in Japanese Patent Laying-Open No. 2009-170501, the surface of workpiece 60 is captured by imaging module 13, thereby recognizing the state of each dividing line 61. Then, based on this recognition result, the amount of conveying the conveying means 20 and the posture/position of holding table 30 are controlled such that workpiece 60 is held on holding table 30 while aligning each dividing line 61 with the position of each cutting blade clearance groove 32. Accordingly, even if workpiece 60 undergoes a pattern displacement of each dividing line 61, workpiece 60 can be held on holding table 30 such that each dividing line 61 is aligned with the position of each cutting blade clearance groove 32. Therefore, an excellent full-cutting operation can be performed in the state where the positions of cutting blade 41, each dividing line 61 and each cutting blade clearance groove 32 are aligned with one another.
According to cutting device 10 disclosed in Japanese Patent Laying-Open No. 2009-170501, however, the following problems arise. For example, in a sealed substrate as a semi-finished product obtained when a product (a semiconductor device) referred to as a BGA (Ball Grid Array) is manufactured (this sealed substrate will be hereinafter referred to as a “BGA substrate”), a large number of solder balls electrically connected to the outside are formed on the substrate. In this BGA substrate, a solder ball may be formed at a position displaced from the position of a dividing line. If the BGA substrate is cut in the state where the position of the solder ball is displaced from the dividing line, a part of the solder ball may be damaged. When the solder ball is damaged, the quality of a singularized BGA product is deteriorated, so that a defective product may be produced.